Web pages, when displayed by a browser, may include content from a number of domains. An in-line frame (iFrame), for example, is one type of markup element that can be placed within a web page to display a hyper-text markup language (HTML) document that is received from a domain different than the main web page.
Communication between an iFrame, associated with one domain, and the main web page (e.g., a container frame), associated with a second domain, can be limited. In some browsers, messages, such as a “postMessage,” can be used to exchange information across domains. Not all browsers, however, support such messages.